KR20090015094A - Pressure sensitive adhesives - Google Patents

Abstract

PSAs with improved resistance to moisture-whitening and high shear stability have been described. PSAs may be selected from a plurality of, preferably three or more aromatic rings, monovalent oxy substituted sulfo anions, and / or monovalent oxy substituted phospho anions, and one or more repeating alkoxy units (eg At least one ionic surfactant comprising at least one substituent including Soprophor 4D 384, and at least one non-ionic surfactant (eg, Abex 2535) and additional non-aromatic ionic surfactants (eg For example, an effective amount of a surfactant mixture comprising Aerosol OT 75); And monomers comprising at least one hydrophobic monomer (component I), at least one hydrophilic monomer (component II) at least one partially hydrophilic monomer (component III) and optionally at least one ureido monomer (eg Norsocryl 102) (component IV) Obtained from an aqueous dispersion comprising the composition. The average particle size of the dispersion is about 100 nm to about 400 nm and the pH is about 5.5 to about 9.0. The latex has good moisture whitening resistance and forms a sufficiently stable PSA under high shear to allow curtain coating.

Description

Pressure sensitive adhesive {PRESSURE SENSITIVE ADHESIVES}

The present invention relates to pressure sensitive adhesives (PSA) based on aqueous emulsions and methods of making the adhesives. The pressure sensitive adhesives of the present invention have improved resistance to water-whitening and can also be resistant to high shear, which allows coating with high speed machines.

There is an increasing demand for providing labels that appear to be invisible to the consumer. This requires a very transparent label adhesive stack (ie, PSA coated fabric) so that when the label is attached to the product, the information appears to be printed directly on it for maximum aesthetic effect. It is also desirable to use aqueous adhesives rather than solvent based adhesives due to environmental and other reasons. Conventional aqueous adhesives, however, exhibit very poor moisture-whitening resistance, where the dried adhesive film quickly turns white when exposed to water. In many applications, the labels are exposed to water where conventional aqueous PSAs can whiten and spoil the desired label-like appearance (eg, labeled beverage containers can be cooled in an ice bath). There is also a need for improved water whitening resistance such that the PSA maintains adhesion between the substrate and the fabric when hot water sprayed or immersed, for example, on bottle labels of pasteurized bottles. In general, resistance to moisture-whitening is desirable wherever a PSA or substrate of transparent fabric is applied to water or high humidity. Examples include labels on the sides of trucks, signals and bottles.

Various adhesives with moisture whitening resistance have been described in the prior art.

Applicant's patent applications: WO 03/006517, WO 03/006518, WO 04/029171, WO 04/029172 and WO 05/044880 describe PSAs with good water whitening resistance.

US 2005/0176876 (Avery) discloses the use of a combination of two specific monomers i) trifluoroalkyl (meth) acrylate and ii) alkylimidazolidone (meth) acrylate to enhance water whitening of PSA. The acrylic PSA compositions mentioned are described.

WO 00/61670 (Ashland) (= EP 1198502-A, US 2004-0076785 and US 6359092) contains water whitening obtained from monomer compositions consisting essentially of C _{> = 4} alkyl acrylates, ethylenically unsaturated acids or anhydrides and styrenes. Resistant PSAs are described. The document teaches that no additional monomer should be used. The document also teaches that the use of redox polymerization initiators is an essential factor in the preparation of the PSA, and that the dispersion phase in the PSA emulsion needs to have an average particle size of 100 nm or less.

WO 01/85867 (Ashland) (= EP 1240267-A, US 2004 0076785 and US 6359092) describes water whitening resistant PSAs obtained using polymeric surfactants of the following structure only as emulsifiers:

_Wherein R ₁ is C _6-18 alkyl, C _6-18 alkenyl, or C _6-18 aralkyl, R ₂ is H or R ₁ , R ₃ is H or propenyl; A is C _2-4 alkylene, n is an integer from 1 to 200 and M is an alkali metal, ammonium ion, or alkanolamine cation. Preferred and illustrative emulsifiers

(Hitenol BC 10). The document does not consider the problem of providing improved adhesion on low energy surfaces.

It was generally believed that there are few aqueous PSAs with acceptable resistance to water bleaching and that there is a limit to the way in which PSAs can be modified without reducing or eliminating desirable water bleaching properties. For example, it was believed that prior art PSAs using conventional surfactants of the prior art have much less resistance to water whitening, and therefore have to polymerize surfactants in latex for optimal water whitening resistance.

High speed coating machines used to apply commercial PSAs at large volumes generate high shear fields. For example, typical equipment such as Moyno pumps, slot dies, pressurized gravures and curtain coaters typically generate shear fields greater than 150,000 s ⁻¹ in the coating head and / or in the propulsion cavity pump. If conventional PSA emulsions are used in the machine, the emulsions destabilize under high shear fields to form coagulum. The coagulum blocks the die, causes scratch lines on the coating web, and creates high pressure in the die and pump. Excess coagulum must therefore be removed, which increases the cost and therefore requires a temporary stop of the coater, which is undesirable.

This limits the commercial use of PSAs with the best water whitening resistance, since polymerizable surfactants reduce the stability of the latex when under high shear, since such PSAs are not readily stable under high shear. Since it is thought to enhance one property that adversely affects other properties, it was believed that there would have been an exchange between water whitening resistance and stability under high shear.

JP 63-27572, for example, describes high stability, high solid acrylic emulsion polymers which are stabilized with a mixture of anionic and nonionic nonpolymerizable surfactants. However, the surfactant mixture is added in large quantities, and the adhesive has poor resistance to moisture whitening.

US5468800 (Rhoem) contains butyl acrylate, methyl methacrylate, methacrylic acid and N- (2-methacryloyloxy ethyl) ethylene urea dispersed with sodium tri-iso-butylphenol (ethoxy) ₇ sulfate. A high pH (2.2) aqueous binder composition containing is described. The reference is not related to PSA and will not be water whitening resistance when the composition is used as PSA.

None of the prior art water whitening PSAs provides a satisfactory answer to the problem of improving latex stability under high shear while maintaining good water whitening resistance. There is also a need for curtain coatable PSAs that have acceptable resistance to moisture whitening.

Therefore, it is an object of the present invention to solve some or all of the problems of the prior art PSA emulsions. The present invention relates to compositions of aqueous adhesives and methods for their preparation in combination with acceptable water whitening resistance and good high shear stability.

Surprisingly, applicants have found adhesive formulations that have acceptable moisture whitening resistance and are also stable under high shear. It is particularly surprising that this is achieved without the use of polymerizable surfactants.

Therefore, in general, according to the invention, (a), (b) suitable for the preparation of pressure sensitive adhesives (PSA) having acceptable, optionally improved resistance to moisture-whitening and acceptable under high shear, optionally improved, stability, An aqueous dispersion is provided comprising (c) and (d):

(a) an effective amount of a surfactant mixture comprising

(i) at least one ionic surfactant comprising

(I) a plurality of, preferably three or more aromatic rings,

(II) one or more negative electrode substituents formed from strong acids, optionally selected from monovalent oxy substituted sulfo anions, and / or monovalent oxy substituted phospho anions, and

(III) optionally one or more substituents comprising multiple hetero-organo units, optionally one or more repeating oxyhydrocarbylene units, which may be the same or different, and

(ii) one or more non-aromatic (optionally non-aromatic), optionally comprising one or more substituents optionally comprising multiple hetero-organo units, optionally one or more repeating oxyhydrocarbylene units, which may be the same or different. Ionic surfactants,

(b) a monomer composition comprising:

(i) at least one hydrophobic polymer precursor (component I)

(ii) at least one hydrophilic polymer precursor (component II)

(iii) at least one partially hydrophilic polymer precursor (component III)

(iv) optionally at least one polymer precursor of formula (component IV)

Formula 4

(In the meal,

Y represents a negative electric group,

R ⁰ is H, OH or optionally hydroxy substituted C _1-10 hydrocarbo,

R ¹ is H or C _1-10 hydrocarbo;

R ² is C _1-10 hydrocarbosubstituted with one or more activated unsaturated moieties;

A represents a divalent organo moiety attached to both the HN and Y moieties such that the A, NH, C═O and Y moieties together represent a ring having from 4 to 8 ring atoms, and R ¹ and R ² on the ring Attached at any suitable point;

When R ¹ and R ² are attached to the R ⁰ moiety, A is absent (ie, Formula 4 is linear and / or branched does not contain a heterocyclic ring);

x is an integer from 1 to 4;

(c) optionally having a pH of about 5.5 to about 9.0; And

(d) optionally having an average particle size of about 100 nm to about 400 nm.

It is preferred that the adhesives of the invention exhibit the following properties:

i) having water bleaching resistance in a proportion of up to 1.5 on a visual scale after soaking in water at 90 ° C. for 20 minutes; And

ii) substantially no coagulum formed when latex was applied to a shear field of at least 4000 s ^{−1 for at} least 2 minutes.

Preferred dispersions of the present invention are substantially free of any surfactant to be polymerized under the polymerization conditions of the monomer composition.

The term strong acid, as used herein, preferably denotes an acid having a pK _a (under the conditions of the process of the invention) of less than about 3, more preferably less than about 2.

The adhesive emulsions of the present invention exhibit acceptable water whitening resistance combined with acceptable stability under high shear. They are suitable for applications such as aqueous adhesives for holding transparent labels and can be applied by a wide variety of high speed methods including curtain coatings.

Moisture bleaching resistance

The pressure sensitive adhesives of the present invention are resistant to moisture whitening. The range of moisture-whitening can be measured using a UV / Visible spectrometer which measures the absorbance visually or as a function of time as described below.

Test strips coated with PSA were typically prepared to test moisture whitening resistance (as described, for example, in the Examples section herein). The PSA strip was immersed in water for 30 minutes at a specific temperature, and then the appearance of the strip was immediately assessed to determine moisture whitening resistance. Test strips can be evaluated visually by grading scale 0 (transparent) to 5.0 (fully whitened / opaque). To aid in visual grading, the test strips can be usefully compared to a series of photographs of standard strips predetermined to have each grade. Alternatively, the evaluation can be measured by an increase in absorbance before and after dipping (as measured by UV / Visible spectroscopy). For example, a suitable level of water bleaching resistance may be when the increase in absorbance is less than 0.2, preferably less than 0.05, after 24 hours of room temperature water soaking. If no temperature is specified herein, immersion takes place at ambient temperature (20 ° C.).

PSAs used in applications such as beverage labels are preferably resistant to moisture whitening at higher temperatures (90 ° C.) as the labeled containers are pasteurized at higher temperatures. However, PSAs that exhibit moisture whitening resistance at lower temperatures are also useful because no pasteurization is needed for other applications (eg, labeling of health and beauty products).

The PSAs of the present invention exhibit acceptable, preferably improved, resistance to moisture whitening at ambient temperatures. More preferred PSAs of the invention exhibit acceptable, most preferably improved water resistance at 90 ° C. (ie they are also pasteurization resistant).

This term, as used herein, is defined as follows for the temperature given after 20 minutes soaking: 'acceptable' moisture whitening resistance means an increase of absorbance of less than or less than 0.2 and a grade of 1.5 or less for the visual scale. do. 'Enhanced' moisture whitening resistance means an increase in visual rating of 0.5 or less and / or absorbance of less than 0.05.

As a comparison, conventional aqueous PSA formulations that are not resistant to water whitening typically have a visual rating of 5.0 after soaking for only 10 minutes at ambient temperature.

High shear stability

High shear as described herein means a shear rate of at least 4000 s ⁻¹ , preferably at least 20,000 s ⁻¹ , more preferably at least 70,000 s ⁻¹ , for example at least 150,000 s ⁻¹ .

Conveniently high shear stability as used herein means that when applied to a shear field of 4000 s ⁻¹ or greater for at least 2 minutes, substantially no coagulum is formed (ie the emulsion or dispersion is unstable More conveniently, good high shear stability means stable above 20,000 s ^-1 for at least 5 minutes, most conveniently improved high shear stability means above 70,000 s ^-1 for at least 10 minutes, For example, optimal high shear stability means that it is stable at least 150,000 s ⁻¹ for at least 10 minutes.

Surfactants

Optionally one or more of the aromatic ionic surfactant (s) has an HLB value of about 8 to about 20, preferably about 10 to about 18, more preferably about 12 to about 17, for example about 16.

Conveniently at least one of the aromatic ionic surfactants is represented by the formula:

Formula 1

(Wherein Ar ¹ and Ar ² each independently represent a C _6-18 hydrocarbo each comprising an aromatic moiety,

L is optionally a divalent organo linking group or a direct bond, wherein Ar ¹ and Ar ² can together form a fused ring;

R ¹ is optionally substituted C _1-8 hydrocarbylene, more preferably C _1-6 alkylene;

X ¹ and X ² independently each occurrence are O, S, CH ₂ , NH or NR ³ , wherein R ³ represents optionally substituted C _1-20 hydrocarbyl, more preferably C _1-10 alkyl Represents;

A represents an S (O) _1-3 or P (O) _1-3 moiety, q is 1 to 3;

C is a suitable counter cation and p is balanced with charge q;

m is 1 to 70, preferably 5 to 60; More preferably 10 to 50; Most preferably an integer from 10 to 30, for example about 16;

n represents an integer of 1 to 6, optionally 1 to 3).

More conveniently, the at least one ionic surfactant of formula 1 is represented by formula 1a:

Formula 2

Wherein L, R ¹ , X ¹ , X ² , A, C, q, p, n and m are as shown in Formula 1, R ² is optionally substituted C _1-8 hydrocarbylene, more preferably Preferably C _1-6 alkylene).

More preferably in the formula (2),

L, R ¹ and R ² in each occurrence are independently C _1-4 alkylene, more preferably -CHCH ₂ (CH ₃ )-, -CH (CH ₃ )-or -CH ₂ CH _2- ,

X ¹ and X ² are each independently O, S, NH or -N (C _1-6 alkyl)-, most preferably O,

A is S (O) ₃ or P (O) ₃ , q is 1,

C is a suitable counter cation, optionally p is 1;

n is 1 to 3, more preferably 3, m is 10 to 30, most preferably 10 to 20, for example 16.

Most preferred surfactants of formulas (1) and (2) are phosphorylation and / or sulfation of alkoxylated polystyryl substituted phenols (such as tristriyl phenol and / or derivatives thereof) obtained after the reaction of styrene with phenol. These are those obtained and / or obtainable by.

Particularly preferred tristriyl phenolic ionic surfactants of formulas (1) and (2) are those available from Rhodia under the following trade names:

Soprophor 3D-33 (ethoxylated phosphate ester free acid);

Soprophor 3D-33 / LN (low non ionic ethoxylated phosphate ester free acid);

Soprophor 3D-FLK (ethoxylated phosphate ester potassium salt);

Soprophor 3D-FL (ethoxylated phosphate TEA (triethylamine) salt);

Soprophor 3D-FL-60 (ethoxylated phosphate TEA (triethylamine) salt);

Soprophor 4D-384 (ethoxylated sulfate, ammonium salt);

Soprophor 4D-360 (ethoxylated sulfate, ammonium salt);

And / or any suitable mixture thereof.

Exemplary surfactants are available from Rhodia under the tradename Soprophor 4D384.

(If the cation is ammonium).

In alternative embodiments, optionally substituted derivatives of alkylene naphthyl sulfonate commercially available from King Industries may be used as the ionic surfactant.

Any non-ionic surfactant can be any suitable surfactant, such as aliphatic nonionic surfactants of Formula 3:

화학식 3

Formula 3

(In the meal,

R ¹¹ is optionally substituted C _1-50 hydrocarbyl, more preferably C _1-30 alkyl; More preferably C _1-20 alkyl;

X ⁴ and X ⁵ independently each occurrence represent O, S, CH ₂ , NH or NR ¹² , wherein R ¹² represents optionally substituted C _1-20 hydrocarbyl (optionally C _1-10 alkyl) , More preferably X ⁴ and X ⁵ are independently O, S, NH or -N (C _1-6 alkyl)-, most preferably O,

Z is C _1-4 alkylene, more preferably -CHCH ₂ (CH ₃ )-, -CH (CH ₃ )-or -CH ₂ CH _2- , CH-CH ₂ or

 Indicates,

'w' represents an integer from 1 to 50, preferably from 1 to 30, more preferably from 5 to 20).

Particularly preferred nonionic surfactants are mixtures of aliphatic nonionic surfactants sold under the trade name Abex 2535 by Rhodia.

The surfactant mixture is optionally from polycarboxylic acids and / or esters substituted with one or more negative electrode substituents formed from strong acids, preferably selected from monovalent oxy substituted sulfo anions, and / or monovalent oxy substituted phospho anions. It may further comprise another ionic surfactant selected.

Preferred other ionic surfactants include those of the formula:

Wherein E is a negative electrode group, preferably SO ₃ or PO ₂ ,

L is a trivalent organo linking group, preferably C _1-4 alkylene;

R ′ and R ″ are each independently H or optionally substituted C _1-30 hydrocarbyl).

Any other ionic surfactant that is more preferred is represented by:

An example of any such ionic surfactant is sodium dioctyl sulfosuccinate sold by Cytec under the trade name Aerosol OT.

The total amount of surfactant used in the preparation of the emulsion of the present invention relative to the total weight of the monomers is about 0.1 to about 5% by weight, preferably about 0.5 to about 2% by weight.

In a further aspect of the invention, there is provided a process for preparing a polymeric latex emulsion suitable for use as a pressure sensitive adhesive, comprising the following steps:

(a) in the presence of an effective amount of a surfactant mixture comprising

(i) at least one ionic surfactant comprising

(I) a plurality of, preferably three or more aromatic rings,

(II) one or more negative electrode substituents formed from strong acids, optionally selected from monovalent oxy substituted sulfo anions, and / or monovalent oxy substituted phospho anions, and

(III) optionally one or more substituents comprising multiple hetero-organo units, optionally one or more repeating oxyhydrocarbylene units, which may be the same or different, and

(ii) one or more non-aromatic (optionally non-aromatic), optionally comprising one or more substituents optionally comprising multiple hetero-organo units, optionally one or more repeating oxyhydrocarbylene units, which may be the same or different. Ionic surfactants,

Forming the following aqueous dispersion:

At least one hydrophobic polymer precursor (component I)

At least one hydrophilic polymer precursor (component II)

One or more partial polymer precursors (component III)

Optionally at least one polymer precursor of formula 4 (component IV, as defined herein),

(b) polymerizing the polymer precursor (s) simultaneously or after formation of the dispersion in step (a) to form a latex emulsion; And

(c) optionally adjusting the pH of the emulsion to a pH of about 6.5 to about 9 with a suitable base;

Wherein said effective amount of surfactant in said mixture is the amount necessary to prepare a pressure sensitive adhesive having:

i) moisture bleaching resistance at a rate of up to 1.5 on a visual scale after soaking in water at 90 ° C. for 20 minutes; And

ii) Sufficient stability when the latex is applied to a shear field of at least 4000 s ^{−1 for at} least 2 minutes so that coagulum is not substantially formed.

In any embodiment of the method of the invention, the method comprises the following additional steps:

Forming an additional effective amount of the mixture from step (a) with a starting amount of thermal polymerization initiator to form a secondary mixture;

Successively adding the formed initiator mixture to the primary dispersion (pre-emulsion) formed from step (a) to polymerize the pre-emulsion to form a latex emulsion, wherein an additional polymerization initiator is added to the Added during polymerization.

Preferably the aqueous dispersion of the present invention comprises about 40% to about 70% by weight of the total dispersion, more preferably about 50% to 65% by weight, most preferably about 55% to about 65% by weight, such as For example, from about 58% to about 62% by weight of total solids.

Usefully in the process of the invention the PSA of the invention is less than about 1.0%, more usefully less than about 0.5%, most usefully less than about 0.2%, such as about 0.1% by weight of the total monomer composition. And is obtainable by polymerization of monomers in the presence of a water soluble initiator in an amount of from about 0.2% by weight.

In another aspect of the present invention, a method of using a surfactant mixture for the purpose of improving water whitening resistance in high shear safety PSA latex is provided wherein the surfactant mixture comprises a plurality of aromatic groups and preferably monovalent oxy substituted Two or more different ionic surfactants comprising at least one negative electrode substituent formed from a strong acid, selected from sulfo anions, and / or monovalent oxy substituted phospho anions (preferably (i) as defined herein At least one ionic surfactant of (1) and (ii) one ionic surfactant of formula (2), optionally at least one non-ionic surfactant.

A further aspect of the invention provides dispersions obtained and / or obtainable from the process of the invention as described herein.

Another additional aspect of the present invention provides pressure sensitive adhesives obtained and / or obtainable from the dispersions of the present invention as described herein.

Another aspect of the invention provides an adhesive laminate comprising a substantially transparent fabric having an adhesive coating and optionally a release liner, wherein the coating is a pressure sensitive adhesive (PSA) of the invention (or herein) described herein. PSA obtained and / or obtainable from the dispersions of the invention as described herein, wherein the laminate exhibits acceptable, optionally improved resistance to water whitening and acceptable, optionally improved high shear.

Another aspect of the invention provides an article and / or container labeled with the adhesive stack of the invention.

A further aspect of the present invention provides a high speed, high shear (optionally at least 4000 s ⁻¹ , preferably at least 20,000 s ⁻¹ , more preferably 70,000 s ⁻ of substrates with a dispersion of the present invention to obtain a film pressure sensitive adhesive. ^A coating method (preferably curtain coating) under ^one or more, for example 150,000 s ⁻¹ or more.

Monomer composition

Unless otherwise indicated (for example, relative to the amount of aryl arylalkylene in component I), all weight amounts described herein for the following monomers are in weight percent of the total weight of monomers (components I, II, III & IV) Presented.

Component I

Hydrophobic monomers (component I) comprise one or more hydrophobic polymer precursors and / or arylalkylene polymer precursors, including one or more activated unsaturated moieties (conveniently one or more hydrophobic (meth) acrylate monomers), conveniently This can be done essentially.

Preferably the hydrophobic (meth) acrylate comprises C _{> 4} hydrocarbo (meth) acrylate (s), and conveniently the C _{> 4} hydrocarbo moiety is C _4-20 hydrocarbyl, more conveniently Can be C _4-14 alkyl, most conveniently C _4-10 alkyl, for example C _4-8 alkyl.

Suitable hydrophobic (meth) acrylate (s) are: isooctyl acrylate, 4-methyl-2-pentyl acrylate, 2-methylbutyl acrylate, isoamyl acrylate, sec-butyl acrylate, n-butyl acrylate , 2-ethylhexyl acrylate, isodecyl methacrylate, isononyl acrylate, isodecyl acrylate, and / or mixtures thereof, in particular 2-ethylhexyl acrylate and / or n-butyl acrylate, for example 2 -Ethylhexyl acrylate.

Preferably the arylalkylene comprises styrene (optionally hydrocarbosubstituted) and conveniently any hydrocarbo may be C _1-10 hydrocarbyl, more conveniently C _1-4 alkyl.

Suitable arylalkylene monomers are selected from: styrene, α-methyl styrene, vinyl toluene, t-butyl styrene, di-methyl styrene and / or mixtures thereof, in particular styrene.

The arylalkylene monomer may be present in component I (total hydrophobic monomer), up to about 30%, preferably from about 1% to about 20%, more preferably from about 5% to about 15% of the total weight of component I. have.

Generally preferred component I is a mixture of 2-ethylhexyl acrylate and / or n-butyl acrylate and styrene, more preferably a mixture of 2-ethylhexyl acrylate and styrene.

Component I may be present in a total amount from about 70% to about 90% by weight, preferably from about 75% to about 85% by weight.

Component II

Suitable hydrophilic polymer precursors of component II are those that are copolymerizable with the hydrophobic polymer precursor (s) of component I and are water soluble. Conveniently one or more hydrophobic polymer precursors may comprise one or more activated unsaturated moieties.

Preferred hydrophilic monomers comprise, advantageously consist essentially of, one or more ethylenically unsaturated carboxylic acids. More preferred acids have one ethylenic group and one or two carboxyl groups. Most preferably the acid (s) are: acrylic acid (and oligomer thereof), beta carboxy ethyl acrylate, citraconic acid, crotonic acid, fumaric acid, itaconic acid, maleic acid, methacrylic acid and mixtures thereof; For example acrylic acid, methacrylic acid, beta carboxy ethyl acrylate and mixtures thereof.

Generally preferred component II is a mixture of beta carboxy ethyl acrylate and acrylic acid.

Component II is at least about 1% by weight, preferably from about 2% to about 10% by weight, more preferably from about 3% to about 9% by weight, most preferably from about 4% to about 8% by weight. May be present in a total amount.

Component III

The partially hydrophilic polymer precursor (s) of component III may also be referred to as partially water soluble monomers and may conveniently comprise one or more activated unsaturated moieties.

Preferred partially hydrophilic monomers comprise, and consist conveniently of, one or more C _1-2 alkyl (meth) acrylates. More preferred partially hydrophilic monomers are: methyl acrylate, methyl methacrylate, ethyl acrylate and mixtures thereof; Most preferably ethyl acrylate, methyl methacrylate, and mixtures thereof, such as ethyl acrylate.

Generally preferred component III is ethyl acrylate.

Component II is 10% by weight or less, preferably about 0.1% to about 5% by weight, more preferably about 0.1% to about 3% by weight, most preferably about 0.5% to about 2.5% by weight of total May be present in amounts.

Component IV

Component IV includes, and conveniently consists of, one or more monomers of Formula 4 as defined herein.

Formula 4

The ring moiety (s) of formula 4 are each attached to R ² , and when x is 2, 3 or 4 in formula 4, R ² is multi-atom (depending on the value of x). When x is not 1, R ¹ and Y may each represent the same or different moiety in each ring, preferably the same moiety in each ring. R ¹ and R ² may be attached at any suitable position on the ring.

Preferred monomers of formula (4) include, and consist essentially of, the following:

A represents any substituted divalent C _1-5 hydrocarbylene;

Y is divalent NR 'wherein R' is H, OH, optionally hydroxy substituted C _1-10 hydrocarbo or R ² , or divalent O.

More preferred monomers of formula 4 include those corresponding to:

x is 1 or 2;

Y is NR ² (ie, where Formula 1 is attached to R ² via ring nitrogen);

A represents divalent C _1-3 hydrocarbylene;

R ⁰ is H,

R ¹ is C _1-10 hydrocarbo;

R ² comprises (meth) acryloxyhydrocarbobolic or a derivative thereof (eg maleic anhydride).

Most preferred monomers of formula 4 include those corresponding to:

x is 1, or 2, and the (optionally repeated) unit in formula (1) is represented by formula (6)

Formula 6

(Wherein the asterisk indicates the point of attachment of formula 6 to R ² (which may be any point on the ring, preferably via ring nitrogen));

R ¹ is H or C _1-8 hydrocarbyl;

R ² comprises (meth) acryloxyC _1-10 hydrocarbogi.

More preferred monomers of formula 4 include:

_Wherein R ¹ is H or C _1-6 alkyl and L is a suitable divalent organo linking group (such as C _1-10 hydrocarbylene, for example C _1-6 alkylene).

Further suitable urethane monomers of formula 4 are all referred to herein as "Novel wet adhesion monomers for use in latex paints" Singh et al, Progress in Organic Coatings, 34 (1998), 214-219, in particular Section 2.2 & 2.3) and EP 0629672 (National Starch).

Examples of monomers of formula 4 are selected from the following and suitable mixtures thereof:

(식 중, n 은 1 내지 4 임),

(Wherein n is 1 to 4),

(Commercially available from Atofina under the trade name Sipomer ^® WAM II).

In the above and / or another embodiment of the invention, monomers as described in US Pat. No. 6,166,220 (Cytec Technology Corporation, the disclosure of which is hereby incorporated by reference) may comprise all or part of component IV and / or formula 4 herein. May be used and / or incorporated into the formulations of the invention. Preferably such monomers are represented by the formula “B (C═O) Y (C═O) A”, wherein B, Y and A are as described therein, in US Pat. No. 6,166,220, column 2, line 25. Such monomers may be commercially available from Cytec under the trade name Cylink ^® . Examples of suitable such monomers are those sold under the following trade names: Cylink ^® NMA and / or NMA-LF (self cross-linking monomer), Cylink ^® IBMA (isobutoxy derivatives of Cylink ^® NMA), Cylink ^® MBA; Cylink ^® NBMA, Cylink ^® TAC and / or Cylink ^® C4 (wet attachment monomer).

Conveniently component IV can be used as a substantially pure compound (or mixture of compounds) of formula 1 or can be dissolved in a suitable solvent such as a suitable (meth) acrylate or acrylic derivative, such as methyl methacrylate. . Optionally such a solution may comprise from about 50% to about 75% by weight of component IV.

Component IV is at least about 0.1% by weight, preferably from about 0.1% to about 2.0% by weight, more preferably from about 0.2% to about 1.0% by weight, most preferably from about 0.3% to about 0.6% by weight. May be present in total amount.

Activated unsaturated moiety

The term “activated unsaturated moiety” is used herein to refer to a species comprising at least one unsaturated carbon to carbon double bond in chemical proximity to one or more active moieties (eg for R ² in Formula 4). . Preferably the activating moiety comprises any group that activates an ethylenically unsaturated double bond for addition by a suitable electrophilic group. Conveniently the activating moiety is an oxy, thio, (optionally organo-substituted) amino, thiocarbonyl and / or carbonyl group (the latter two groups being optionally substituted by thio, oxy or (optionally organo-substituted) amino) It includes. More convenient activation moieties are (thio) ether, (thio) ester and / or (thio) amide moiety (s). The most convenient "activated unsaturated moieties" include one or more "hydrocarbylideneyl (thio) carbonyl (thio) oxy" and / or one or more "hydrocarbylideneyl (thio) carbonyl (organo) amino" groups. “Unsaturated ester moieties” and / or derived moieties that represent organo species and / or analogues, such as moieties comprising (meth) acrylate functionalities and / or derivatives thereof. An "unsaturated ester moiety" may optionally include other derivatives and analogs thereof, including optionally substituted general α, β-unsaturated acids, esters and / or thio derivatives.

Preferred activated unsaturated moieties are those represented by the radicals of the formula (5), and all suitable isomers thereof, combinations thereof for the same species and / or mixtures thereof:

Formula 5

Wherein n ′ is 0 or 1, X ⁶ is oxy or thio; X ⁷ is oxy, thio or NR ¹⁷ , wherein R ¹⁷ represents H or optionally substituted organo, and R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ each independently represent a bond to another moiety of formula 1, H, an optional substituent and / or an optionally substituted organo group, wherein R ¹³ , R ¹⁴ , R ¹⁵ and R Any of ¹⁶ may be joined to form a ring, wherein at least one of R ¹³ , R ¹⁴ , R ^15, and R ¹⁶ is a bond).

The term "activated unsaturated moiety"; “Unsaturated ester moiety” and / or Formula 5 herein refers to some of the formulas herein, wherein the term as used herein may be part within a formula, which may be monovalent or multivalent (eg, bivalent). The radical part according to where it is located is indicated. Thus, for example in formula (4), at least one of R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ will be recognized to represent a single covalent bond, ie to indicate where formula 5 is attached to the rest of formula (4). .

More preferred moieties of formula 5 (including isomers and mixtures thereof) are those wherein X ⁶ is O; X ⁷ are those which are O, S or NR ⁷ .

R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ are independently selected from: a bond, H, an optional substituent and an optionally substituted C _1-10 hydrocarbo, optionally R ¹⁵ and R ¹⁶ are linked (to which they are attached Together with the moiety) to form a ring; R ¹⁷ present here is selected from H and optionally substituted C _1-10 hydrocarbo.

Most preferably n 'is 1 and X ⁶ is O; X ⁷ is O or S and R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ are independently a bond, H, hydroxy and / or optionally substituted C _1-6 hydrocarbyl.

For example, n 'is 1 and X ⁶ and X ⁷ are both O; R ³ , R ⁴ , R ⁵ and R ⁶ are independently a bond, H, OH, and / or C _1-4 alkyl; Or optionally R ⁵ and R ⁶ together are a divalent C _0-4 alkylene-carbonyl C _0-4 it is possible to form an alkylene portion Formula 5 represents a cyclic anhydride (e.g., R ¹⁵ and R ¹⁶ is When together with carbonyl, Formula 5 represents maleic anhydride or derivative thereof).

For n 'is 1 and X ⁶ and X ⁷ are both O and one of (R ¹³ and R ¹⁴ ) is H and R ¹³ is H, for the part of Formula 5, Formula 5 represents an acrylate moiety And acrylates (if both R ¹³ and R ¹⁴ are H) and derivatives thereof (if R ¹³ and R ¹⁴ are not H). Similarly, when one of (R ¹³ and R ¹⁴ ) is H and R ¹⁵ is CH ₃ , Formula 5 represents a methacrylate moiety, where methacrylate (where both R ¹³ and R ¹⁴ are H) And derivatives thereof (when R ¹³ and R ¹⁴ are not H). Particular preference is given to the acrylate and / or methacrylate moieties of formula (5).

Conveniently, the moiety of formula 5 has n 'of 1; X ⁶ and X ⁷ are both O; R ¹³ and R ¹⁴ are independently a bond, H, CH ₃ or OH, and R ¹⁵ is H or CH ³ ; R ¹⁶ is H, or R ¹⁵ and R ¹⁶ are together divalent C═O groups.

More conveniently, the portion of formula 5 is n 'is 1; X ⁶ and X ⁷ are both O; R ¹³ is OH, R ⁴ is CH ₃ , R ¹⁵ is H, and R ⁶ is a bond and / or its tautomer (s) (eg of acetoacetoxy functional species).

The most convenient unsaturated ester moiety is -OCO-CH = CH ₂ ; -OCO-C (CH ₃ ) = CH ₂ ; Acetoacetoxy, -OCOCH = C (CH ₃ ) (OH) and all suitable tautomer (s) thereof.

It will be apparent that any suitable moiety represented by formula 5 may be used in the context of the present invention as other reactive moieties.

General

As used herein, the terms 'optional substituents' and / or 'optionally substituted' (unless following the list of other substituents) mean one or more of the following groups (or substitutions by these groups): carboxy, sulfo, Formyl, hydroxy, amino, imino, nitrilo, mercapto, cyano, nitro, methyl, methoxy and / or combinations thereof. Any such group includes any chemically possible one of the plurality of (preferably two) identical moieties of the above-mentioned groups (e.g., amino and sulfonyl represent sulfamoyl groups when not directly attached to one another) Combinations are included. Preferred optional substituents include: carboxy, sulfo, hydroxy, amino, mercapto, cyano, methyl, halo, trihalomethyl and / or methoxy.

As used herein, the synonymous terms 'organic substituent' and 'organic' (also abbreviated herein as "organo") are any monovalent or multivalent moieties comprising one or more carbon atoms and optionally one or more other heteroatoms. (Optionally attached to one or more other parts). The organic group is organic, but may include an organoheteroyl group (also an organoelement group) having a free valence (eg, an organothio group) at an atom other than carbon, including a monovalent group containing carbon. The organic group may alternatively or additionally comprise an organyl group comprising any organic substituent, regardless of the functional group type, having one free valence at the carbon atom. The organic group may also include heterocyclyl groups comprising a monovalent group formed by removing a hydrogen atom from any ring atom of a heterocyclic compound (cyclic compounds having atoms of two or more different elements as ring members, in this case Carbon)). Preferably the non-carbon atoms in the organic group can be selected from: hydrogen, halo, phosphorus, nitrogen, oxygen, silicon and / or sulfur, more preferably hydrogen, nitrogen, oxygen, phosphorus and / or sulfur. Convenient phosphorus containing groups are: phosphinyl (ie '-PR ₃ ' radicals, wherein R independently represents H or hydrocarbyl); Phosphinic acid group (s) (ie, the '-P (= 0) (OH) ₂ 'radical); And phosphonic acid group (s) (ie, a '-P (= 0) (OH) ₃ ' radical).

Most preferred organic groups, optionally in combination with one or more of the following heteroatom containing moieties: (oxy, thio, sulfinyl, sulfonyl, amino, imino, nitrilo and / or combinations thereof), include the following carbon containing moieties: (alkyl , Alkoxy, alkanoyl, carboxy, carbonyl, formyl and / or combinations thereof). The organic group includes all of the (preferably two) identical moieties of the aforementioned carbon containing and / or heteroatom moieties (eg, alkoxy and carbonyl represent alkoxycarbonyl groups when not directly attached to one another). Chemically possible combinations are included.

The term 'hydrocarbo', as used herein, is a sub-set of organic groups and denotes any monovalent or multivalent moiety (optionally attached to one or more other moieties) consisting of one or more hydrogen atoms and one or more carbon atoms and And one or more saturated, unsaturated and / or aromatic moieties. Hydrocarbogi can include one or more of the following groups. Hydrocarbyl groups include monovalent groups formed by removing hydrogen atoms from hydrocarbons (eg alkyl). Hydrocarbylene groups include divalent groups formed by removing two hydrogen atoms from a hydrocarbon, the free valences of which are not included in a double bond (eg, alkylene). Hydrocarbylidene groups include a divalent group formed by removing two hydrogen atoms from the same carbon atom of a hydrocarbon, which may be represented by "R ₂ C =", and its free valency is a double bond (for example , Alkylidene). Hydrocarbylidine groups include trivalent groups (which may be represented by “RC ′”) formed by removing three hydrogen atoms from the same carbon atom of a hydrocarbon, the free valences of which are triple bonds (eg, Alkylidine). Hydrocarbo may also contain saturated carbon to carbon single bonds (eg in alkyl groups) in the same moiety and where they can be substituted with other functional groups; Unsaturated double and / or triple carbon to carbon bonds (eg in alkenyl and alkynyl groups, respectively); Aromatic groups (eg, aryl groups) and / or combinations thereof.

As used herein, the term 'alkyl' or equivalent thereof (eg, 'alk') is any other hydrocarboic, such as those described herein, unless specifically indicated otherwise contextually in a suitable place. For example, double bonds, triple bonds, aromatic moieties (such as alkenyl, alkynyl and / or aryl, respectively) and / or combinations (eg, aralkyl) as well as any polyhydric hydros that link two or more moieties. Carbo species (such as divalent hydrocarbylene radicals, such as alkylene).

Any radical group or moiety referred to herein (eg as a substituent) is a divalent hydro which, unless stated otherwise or otherwise clearly indicated in context (eg, connects two different moieties) Carbylene moiety) polyvalent or monovalent radicals. However, where noted herein, such unit or multivalent groups may also include any substituents. Groups comprising three or more atomic chains represent groups in which the chain may be wholly or partially linear, branched, and / or form a ring (including spiro and / or fused rings). The total number of specific atoms is shown for specific substituents, for example, C _{1 -N} organo represents an organo moiety having 1 to N carbon atoms. In any of the formulas herein, when one or more substituents are not indicated to be attached to any particular atom of the moiety (eg, on a particular position along a chain and / or ring) the substituents may be substituted with any H And / or may be located at any possible position in a chemically suitable and / or effective portion.

Preferably any organo group listed herein comprises 1 to 36 carbon atoms, more preferably 1 to 18 carbon atoms. It is particularly preferred that the number of carbon atoms in the organo group is 1 to 12, in particular 1 to 10, for example 1 to 4 carbon atoms.

Some of the formulas and moieties described herein include polyhetero-organo, preferably polyoxyhydrocarbylene; More preferably it comprises repeating units which may comprise polyoxyalkylenes such as suitable unsubstituted or substituted alkylene groups such as ethylene, propylene, butylene and isobutylene. The term multiple repeat units in this context is the same where such moieties described and presented herein occur singly and / or multiple times to refer to homo--, block and / or random polymeric moieties and / or any suitable mixtures thereof. And / or different repeating units.

Chemical terms as used herein (in addition to the IUAPC name for specifically identified compounds) including the features indicated in parentheses (such as (alkyl) acrylates, (meth) acrylates and / or (co) polymers) are parentheses The part inside indicates that the context is optional, for example, the term (meth) acrylate refers to both methacrylate and acrylate.

Certain portions, species, groups, repeat units, compounds, oligomers, polymers, materials, mixtures, compositions and / or formulations included and / or used in some or all of the invention as described herein may be modified in one or more different forms, For example, it may exist as any of the following incomplete list: stereoisomers (such as enantiomers (eg, E and / or Z forms), diastereomers and / or geometric isomers); Tautomers (eg, keto and / or enol forms), isoforms, salts, zwitterions, complexes (such as chelates, clathrates, crown compounds, cyptands / cryptades, inclusions) Compounds, intercalation compounds, interstitial compounds, ligand complexes, organometallic complexes, non-stoichiometric complexes, π-additives, solvents and / or hydrates); Isotopically substituted forms, polymeric arrangements [eg, homologous or copolymeric, random, graft and / or block polymers, linear and / or branched polymers (eg, star and / or lateral branches), crosslinked and / or Network polymers, polymers obtainable from divalent and / or trivalent repeat units, dendrimers, polymers of different stereoregularity (eg, isotropic, orderly or hybridizable polymers); Polymorphs (eg, crevice forms, crystalline forms and / or amorphous forms), different phases, solid solutions; And / or possible combinations thereof and / or mixtures thereof. The present invention includes and / or uses all such forms as defined herein.

The polymers of the present invention may be prepared by one or more suitable polymer precursor (s), which may be organic and / or inorganic, and may be substituted by another or each polymer precursor (through direct bond (s) as indicated herein). (S) and any suitable (co) monomer (s), (co) polymers (s), including moieties capable of forming bonds with their or respective polymer precursor (s) to provide chain extension and / or crosslinking. S) [including homopolymer (s)] and mixtures thereof.

The polymer precursors of the present invention may comprise one or more monomer (s), oligomer (s), polymer (s); Mixtures and / or combinations thereof having suitable polymerizable functional groups.

Monomers are substantially monodisperse compounds of polymerizable low molecular weight (eg less than 1000 Daltons).

Polymers are polydisperse mixtures of high molecular weight (eg thousands of Daltons) macromolecules prepared by polymerization, where large molecules of smaller units (which themselves can be monomers, oligomers and / or polymers) Addition or removal of one or several units (including multiple repetitions) (if the properties are not critical depending on the details of the molecular structure) has a negligible effect on the properties of the large molecules.

An oligomer is a polydisperse mixture of molecules having an intermediate molecular weight between the monomer and the polymer, the molecule comprising some number of monomer units, and one or several removal thereof will significantly change the properties of the molecule.

Depending on the context, the term polymer may or may not include oligomers.

The polymer precursors of the present invention and / or used in the present invention may be prepared by direct synthesis or by polymerization (if the polymeric precursor is itself polymeric). When polymerizable polymers are themselves used as polymer precursors of the present invention and / or used in the present invention, such polymer precursors have side effects, the number of by-products and / or polydispersities in any polymeric material formed from the polymer precursors. It is preferred to have low polydispersity in order to minimize the viscosity, more preferably substantially simple dispersion. The polymer precursor (s) may be substantially unreactive at room temperature and pressure.

Except as indicated herein, the polymers and / or polymeric polymer precursors of the present invention and / or used in the present invention may be (co) polymerized by any suitable polymerization means well known to those skilled in the art. Examples of suitable methods include: thermal initiation; Chemical initiation by addition of a suitable agent; Catalysis; And / or irradiation with a suitable wavelength such as UV after initiation using any initiator, for example electromagnetic radiation (photo-chemical irradiation); And / or other types of radiation, such as electron beams, alpha particles, neutrons and / or other particles.

Substituents for repeat units of polymers and / or oligomers may be selected to improve the miscibility of materials with polymers and / or resins that may be formulated and / or incorporated for the uses described herein. Therefore, the size and length of the substituents may be chosen to optimize physical entanglement or interlocation with the resins, or they may suitably include other reactive entities capable of chemically reacting and / or crosslinking with these other resins. It can or cannot be included.

Particle size

Applicant has surprisingly found that the PSAs of the present invention can be prepared with larger particle sizes than previously thought to be necessary for water whitening resistance, and the PSA still retains acceptable tolerance to water whitening. There is an advantage of the method to using larger particle sizes (eg, reduced viscosity), and in preferred embodiments of the invention, the particle size of the PSA is greater than 100 nm, conveniently from about 100 nm to about 400 nm. More conveniently from about 200 nm to about 300 nm. The particle size herein is a number average which can be measured by any suitable method such as light scattering.

Other ingredients

Surfactant packages selected for polymerization in the compositions of the present invention are substantially free of undesirable alkyl phenol ethoxylates (APEO) for environmental reasons. Another stable operating condition is still achieved with a decrease in polymer roughness and good water whitening resistance of the PSA in the final polymer emulsion when applied with stable pre-emulsions and coatings.

The final emulsion of the invention is shear stability under a defined range of shear rates. For example, the latex remains stable when applied to 150,000 s ⁻¹ high shear fields. Shear stability is further added by selecting additional suitable additives (such as additional surfactants, blowing agents and / or rheological modifiers) to further control the colloidal stability and rheology of the dispersion without adversely affecting water whitening resistance. Can be increased.

The method (s) of the present invention also employ one or more water soluble polymerization initiators. Any conventional water soluble polymerization initiator that is normally acceptable for emulsion polymerization of acrylate monomers can be used and such polymerization initiators are well known in the art. Typical concentrations of the water soluble polymerization initiator are from about 0.01% to about 1% by weight, preferably from about 0.01% to about 0.5% by weight of the total weight of the monomers filled in the pre-emulsion. The water soluble polymerization initiator may be used alone or in one or more conventional reducing agents such as bisulfite, metabisulfite, ascorbic acid, sodium formaldehyde sulfoxylate, iron sulfate, iron ammonium sulfate, iron ethylenediamine-tetraacetic acid, and the like. It can be used in combination. Water soluble polymerization initiators which can be used according to the invention include water soluble persulfates, peroxides, azo compounds and the like, and mixtures thereof. Examples of water soluble initiators include persulfates (eg, potassium persulfate, and sodium persulfate), peroxides (eg, hydrogen peroxide, and tert-butyl hydroperoxide), and azo compounds (eg, 4, 4'-azobis (4-cyano-pentanoic acid), V-501 from Wako Chemicals), but is not limited thereto. Current preferred water soluble polymerization initiators are persulfates, in particular potassium or sodium persulfate.

The amount of water soluble or water dispersible surfactant added to the mixture of water, monomers and polymerization initiator is an amount effective to prepare a latex emulsion having particles having an average particle size described herein. The effective amount necessary to obtain the desired particle size will depend on the working conditions known in the art to have an effect on the particle size, including stirring (shear), viscosity, and the like. The remaining surfactant may be added at the start of the polymerization to form a pre-emulsion, together with the monomers and / or in the batch during the polymerization.

The polymerization can be initiated by any conventional method known to those skilled in the art, such as by application of heat or radiation (but preferably heat). The method of initiation will depend upon the water soluble polymerization initiator used and will be readily apparent to those skilled in the art.

The water soluble polymerization initiator can be added to the polymerization reaction in any conventional manner known in the art. In general, it is preferred to add a portion of the initiator to the initial reactor charge comprising water, an effective amount of a water soluble or water dispersible surfactant, and an initial amount of polymerization initiator. The remaining initiator can be added continuously or incrementally during emulsion polymerization. In general, it is desirable to add the remaining initiators.

After polymerization, the pH of the latex emulsion is preferably the amount necessary to increase the latex emulsion and a suitable base to increase the pH to about 5.5 to about 9, more preferably about 6.5 to about 8, most preferably about 7 to about 8. Adjust by touching. Examples of suitable bases for adjusting the pH of the latex emulsion include alkali metal hydroxides, alkaline earth metal hydroxides, ammonium hydroxides, amines, and the like and mixtures thereof. In general, a preferred base for use in the present invention is ammonium hydroxide.

The polymerization reaction can be carried out in any conventional reaction vessel capable of emulsion polymerization.

The polymerization can be carried out at temperatures typical for emulsion polymerization. The polymerization is preferably carried out at a temperature in the range of about 50 ° C. to about 95 ° C., preferably in the range of about 60 ° C. to about 85 ° C.

Polymerization time is the time required to achieve the desired conversion based on other reaction conditions, such as temperature profiles and reaction components such as monomers, initiators and the like. Polymerization times will be readily apparent to those skilled in the art.

Many other variations of the invention will be apparent to those skilled in the art, and such modifications fall within the broad scope of the invention.

Unless otherwise clearly indicated in context, the plural forms of the term herein as used herein are to be interpreted as including a single form and vice versa.

The term "comprising" as used herein is incomplete in the following list and includes any other additional suitable items, such as one or more additional feature (s), component (s), material (s) and It will be understood that it may or may not contain substituent (s).

The terms 'effective', 'acceptable' 'active' and / or 'suitable' (e.g., suitably any process, use, method, application, manufacture, product, material of the invention and / or described herein) , Formulations, compounds, monomers, oligomers, polymer precursors, and / or polymers), when used in the correct manner, provide the necessary properties to which they are added and / or incorporated so as to be useful as described herein. It will be understood to refer to this characteristic of the invention. Such utility can be used directly, for example, where the material has the necessary properties for the above-mentioned uses and / or for example, the use of the material as a synthetic intermediate and / or diagnostic tool in the manufacture of other materials for direct use. It can be used indirectly where it is. This term as used herein also denotes that the functional group is miscible in producing an effective, acceptable, active and / or suitable final product.

Preferred usefulness of the present invention includes the use as pressure sensitive adhesives, preferably having sufficient stability in high shear fields to allow improved moisture whitening resistance and curtain coatability.

Further aspects of the invention and preferred features thereof are presented in the claims.

The invention will now be described in detail with reference to the following non-limiting examples, which are merely a way of illustration.

Abbreviation of the material

AA acrylic acid

Abex 2535 fatty ethoxylate nonionic surfactant, buy rhodia

Biocides containing Acticide MBS 1,2-benzisothiazolin-3-one and 2-methyl-4-isothiazolin-3-one

Buy Aerosol OT-75 Sodium Dioctylsulfosuccinate (or AOT), Cytec

DDM n-dodecyl mercaptan

DI water deionized water

EA: ethyl acrylate

EHA: 2-ethylhexyl acrylate

70% aqueous dispersion of Luperox H70 tetra-butyl hydrogen peroxide (TBHP)

NaPS Sodium Persulfate

NH ₄ OH: ammonium hydroxide (28%)

Norsocryl 102: 75/25 mixture of methyl methacrylate and (2-methacryloxyethyl) heteromonocycle (ureido monomer)

5% Aqueous Dispersion Of Rongalit C Sodium Formaldehyde Sulfoxylate

Sipomer β-carboxyethyl acrylate, oligomer of acrylic acid, or β [beta] CEA

Soprophore 4D384 Sulfated Polyarylphenol Etolate, Ammonium Salt

STY Styrene

Example 1

PSA latex was prepared in a jacketed reactor equipped with a reflux condenser, thermocouple and double blade stirrer.

The composition of this example polymer is 2-ethylhexyl acrylate / butyl acrylate / styrene / ethyl acrylate / acrylic acid / beta-CEA / nDDM / Norsocryl 102. During the process, a portion of the deionized water, the surfactant and the monomers were mixed to form a moderately thin, white pre-emulsion in the separation retardation tank. The polykettle was filled with the remaining deionized water. Sodium persulfate solution was prepared in a second separator. The jacket of the multicooker was heated until the multicooker mixture reached 82 ° C., at which point a portion of the initiator solution was filled over 5 minutes. Immediately, preliminary emulsion delay and initiator delay were started. Ebi emulsion delay period was 200 minutes, initiator delay period was 210 minutes. The reaction temperature was kept at 83 ° C. during the delay. At the end of the initiator delay, the reactor contents were held at 86 ° C. for 60 minutes. After the holding period, the reaction temperature was cooled to 57 ° C and a redox initiator system was added after the polymerization. The batch was held at 55 ° C. for 20 minutes and cooled to 45 ° C. A small amount of deionized water charge and ammonium hydroxide were then added to adjust the pH to within the range of 6.3 to 7.5 as measured using a pH meter. Total solids was 61.00%.

Neutralizing latex was coated directly onto 1 mil Mylar film. The film was air dried for 10 minutes and heat dried at 90 ° C. for 5 minutes. Coated Mylar was laminated with release paper (direct coating). For the water whitening / moisture immersion test, the release paper was removed and the polymer surface was exposed to water.

Moisture whitening resistance was visually evaluated as described herein to confirm that it was acceptable. The latex was also sufficiently stable under high shear to be coatable on label fabrics using curtain coaters.

Claims (10)

Suitable for the preparation of pressure sensitive adhesives having acceptable, optionally enhanced, resistance to moisture-whitening and high shear under acceptable, optionally improved, stability, the following (a), (b), (c ) And (d) an aqueous dispersion comprising: (a) an effective amount of a surfactant mixture comprising (i) at least one ionic surfactant comprising (I) a plurality of, preferably three or more aromatic rings, (II) one or more negative electrode substituents formed from strong acids, optionally selected from monovalent oxy substituted sulfo anions, and / or monovalent oxy substituted phospho anions, and (III) optionally one or more substituents comprising multiple hetero-organo units, optionally one or more repeating oxyhydrocarbylene units, which may be the same or different, and (ii) one or more non-aromatic (optionally non-aromatic), optionally comprising one or more substituents optionally comprising multiple hetero-organo units, optionally one or more repeating oxyhydrocarbylene units, which may be the same or different. Ionic surfactants, (b) a monomer composition comprising: (i) at least one hydrophobic monomer (component I) (ii) at least one hydrophilic monomer (component II) (iii) at least one partially hydrophilic monomer (component III) (iv) optionally at least one monomer of formula (component IV)

Formula 4 (In the meal, Y represents a negative electric group, R ⁰ is H, OH or optionally hydroxy substituted C _1-10 hydrocarbo, R ¹ is H or C _1-10 hydrocarbo; R ² is C _1-10 hydrocarbosubstituted with one or more activated unsaturated moieties; A represents a divalent organo moiety attached to both the HN and Y moieties such that the A, NH, C═O and Y moieties together represent a ring having from 4 to 8 ring atoms, and R ¹ and R ² on the ring Attached at any suitable point; When R ¹ and R ² are attached to the R ⁰ moiety, A is absent (ie, Formula 4 is linear and / or branched does not contain a heterocyclic ring), x is an integer from 1 to 4; (c) optionally having a pH of about 5.5 to about 9.0; And (d) optionally having an average particle size of about 100 nm to about 400 nm. Pressure sensitive adhesives (PSA) obtainable from the dispersion of claim 1 having the following properties: i) having water bleaching resistance in a proportion of up to 1.5 on a visual scale after soaking in water at 90 ° C. for 20 minutes; And ii) substantially no coagulum formed when the dispersion was applied to a shear field of at least 4000 s ^{−1 for at} least 2 minutes. The dispersion or PSA according to claim 1 or 2, wherein at least one of the aromatic ionic surfactants is represented by the following general formula (1):

Formula 1 (Wherein Ar ¹ and Ar ² each independently represent a C _6-18 hydrocarbo each comprising an aromatic moiety, L is optionally a divalent organo linking group or a direct bond, wherein Ar ¹ and Ar ² can together form a fused ring; R ¹ is optionally substituted C _1-8 hydrocarbylene; X ¹ and X ² independently each occurrence represent O, S, CH ₂ , NH or NR ³ , wherein R ³ represents optionally substituted C _1-20 hydrocarbyl; A represents an S (O) _1-3 or P (O) _1-3 moiety, q is 1 to 3; C is a suitable counter cation and p is balanced with charge q; m represents an integer from 1 to 50; n represents an integer of 1 to 6). 4. A dispersion or PSA according to claim 3, wherein formula (1) is represented by formula (1a):

Formula 1a Wherein L, R ¹ , X ¹ , X ² , A, C, q, p, n and m are as shown in Formula 1 and R ² is optionally substituted C _1-8 hydrocarbylene. A compound according to claim 4 wherein L, R ¹ and R ² in each occurrence are independently C _1-4 alkylene, X ¹ and X ² are each independently O, S, NH or —N (C _1-6 alkyl)-, A is S (O) ₃ or P (O) ₃ , q is 1, C is a suitable counter cation, optionally p is 1; n is 1-3 and m is 10-30, or a dispersion or PSA. The dispersion or PSA according to any one of claims 1 to 5, wherein at least one of the aromatic ionic surfactants is of the formula:

The dispersion or PSA according to any one of claims 3 to 6, wherein any further ionic surfactant is represented by the formula:

(In the meal, E is a negative electrode group, preferably SO ₃ or PO ₂ , L is a trivalent organo linking group, preferably C _1-4 alkylene; R ′ and R ″ are each independently H or optionally substituted C _1-30 hydrocarbyl). 8. A dispersion or PSA according to claim 7, wherein the further ionic surfactant is represented by the formula:

The dispersion or PSA according to any one of claims 1 to 8, wherein the non-ionic surfactant is represented by the following general formula (3):

Formula 3 (In the meal, R ¹¹ represents optionally substituted C _1-50 hydrocarbyl; X ⁴ and X ⁵ independently each occurrence represent O, S, CH ₂ , NH or NR ¹² , wherein R ¹² represents optionally substituted C _1-20 hydrocarbyl, Z represents C _1-4 alkylene, 'w' represents an integer from 1 to 50). A process for preparing a polymeric latex emulsion suitable for use as a pressure sensitive adhesive, comprising the following steps: (a) in the presence of an effective amount of a surfactant mixture comprising (i) at least one ionic surfactant comprising (I) a plurality of, preferably three or more aromatic rings, (II) one or more negative electrode substituents formed from strong acids, optionally selected from monovalent oxy substituted sulfo anions, and / or monovalent oxy substituted phospho anions, and (III) optionally one or more substituents comprising multiple hetero-organo units, optionally one or more repeating oxyhydrocarbylene units, which may be the same or different, and (ii) one or more non-aromatic (optionally non-aromatic), optionally comprising one or more substituents optionally comprising multiple hetero-organo units, optionally one or more repeating oxyhydrocarbylene units, which may be the same or different. Ionic surfactants, Forming the following aqueous dispersion: At least one hydrophobic polymer precursor (component I) At least one hydrophilic polymer precursor (component II) One or more partial polymer precursors (component III) Optionally at least one polymer precursor of formula 4 (component IV, as defined herein), (b) polymerizing the polymer precursor (s) simultaneously or after formation of the dispersion in step (a) to form a latex emulsion; And (c) optionally adjusting the pH of the emulsion to a pH of about 6.5 to about 9 with a suitable base; Wherein said effective amount of surfactant in said mixture is the amount necessary to prepare a pressure sensitive adhesive having: i) moisture bleaching resistance at a rate of up to 1.5 on a visual scale after soaking in water at 90 ° C. for 20 minutes; And ii) Sufficient stability when the latex is applied to a shear field of at least 4000 s ^{−1 for at} least 2 minutes so that coagulum is not substantially formed.